Answer: Paul, the date of manufacture is important. All Amaircare 3000 and 2500 air purifiers made in 2016 take a 16 Inch Easy Twist HEPA Filter. Units made prior to 2016 take 16 Inch Moulded HEPA Filter.The other filter kits have changed a little, i.e. the number of filters have changed and the types of filters.

HEPA filters usually are effective for 2 to 3 years if pre-filters are changed regularly. Another variable is the amount of dust, dirt, etc. in the air around the unit. Wipe off the outside of the metal cabinet weekly or more often. Change the outer filter every 3 to 4 months. Change the inner filter every 6 months. You can vacuum dust off the outer filter with a vacuum cleaner. The woven material is a carbon blanket as is the inner filter. Neither are washable. Carbon blanket media removes VOC's (volatile organic compounds like formaldehyde, paint thinner, etc.)

Americair manufactures its own Amaircare® brand HEPA filters in Canada. Filament is bonded to air filter media for structural support and even pleat spacing. After pleating, filters are enclosed in protective screens and cast in food-grade plastisol at both ends for a 100% air seal. 100 square feet of HEPA filtration material captures the smallest particulates. Each Amaircare HEPA filter is then tested for 99.97% efficiency, with a laser particle counter.

The Amaircare 3000 Moulded HEPA filter is a 16 inch cartridge filter that also fits the Amaircare 3050 and and Amaircare 4000. (These units are no longer made.) The same intervals should be followed for the other Amaircare air purifiers which include the Amaircare 2500 and the Roomaid with the VOC canister filter or with the standard HEPA and pre- and post-filters. VOC cartridge filters can be added to all these air purifiers.

Important: Always replace a HEPA air filter if an air purifier is turned off for more than 3 to 5 days. HEPA is a medium in which bacteria, viruses, etc. can grow if moisture collects in the filter media. Constant air flow keeps the HEPA filter media dry and free of such contaminants. Every few weeks, I take my canister vacuum cleaner into the bedroom, remove the outer filter, lay it on the floor and vacuum it off with the floor tool. Then I wipe out the interior with a microfiber cloth.